keep in mind the basic trig equation, length of an arc (s) = radius of curvature ® * degree through which arc curves (in radians NOT degrees)

so for a 3" radius curve, for 90 degree bend (but convert to radians by multiplying by pi/180),

arc length (s) = 3" * [ 90 * (pi/180) ]

s = 3" * 1.5707 = 4.7115"

So basically just add that length in your calculations to find the total length of the piece you need to cut then kerf away!

thanks man.

something I wish I would have never showed pics of

Don't get me wrong. You're a bad ass builder, but it's basic geometry. Someone would have figured it out anyway. Hell i didn't even calculate anything on mine. Just cut and tested it. If you make more cuts then necessary it doesn't matter because you are going to glue/glass the shit out of it.